First I want to point out to NEVER DISASSEMBLE THE GEAR PUMP. There is no reason to. The Gears are not available, even the O Rings that go between the layers of the assembly are NOT available. You cannot get the Pump Shaft Seal out from the back side, it must be pulled from the top. A standard auto parts store seal puller for less than $20 will do the job perfectly.

http://meyerplowhelp.com/forums/attachment.php?attachmentid=58&stc=1

With the Pump Shaft Seal removed you can see there is no access to the back side of it. Be VERY careful not to gouge the bore when using the Seal Puller because there is no fix if you gouge it. The Gear Pump WILL leak and need to be replaced.

http://meyerplowhelp.com/forums/attachment.php?attachmentid=59&stc=1
A new Pump Shaft Seal is installed using an 11/16" socket and an Arbor Press, or a hammer. Most Pump Shaft Seals come coated, so there is no additional sealant necessary. IF you like to tinker, then a cheap $50 arbor press would be a great investment and make your life A LOT easier. Take your pick, all the cheap ones are about the same, and work well for small seal installs.
http://meyerplowhelp.com/forums/attachment.php?attachmentid=60&stc=1